Add-on sync and two new developer tools are the hallmarks of today's update to Firefox.

The stable version of the browser that you can download now, Firefox 11 (download for Windows | Mac | Linux) allows you to mirror the same add-ons across multiple desktops. While it's true that Google Chrome has been able to sync add-ons since late 2010, its implementation has been notably uneven. It'll be interesting to see how well Firefox handles it. You can toggle add-on synchronization from the Sync tab in the Options window.

A Mozilla representative told CNET that there would be no major update to Firefox for Android today. Although the mobile version of the browser had been on the same six-week release cycle as the desktop version, Mozilla's decision to change to a native Android interface has prevented more major updates from being pushed to the browser since January.

Along with add-on sync, Firefox now marks most add-ons as compatible by default.

Firefox 11 also adds two new options to a developer's toolbox. The first is the 3D Page Inspector View nicknamed Tilt. Not unlike steroids for "View Source," Tilt is a WebGL-powered option to highlight what raw code looks like when the public sees it on a live Web site. Mozilla anticipates that this will help show the connection between code and site experience.

Unique to Firefox, Tilt can be turned on by choosing 3D in View in Page Inspector. Hover over an element to see more about it.

The second tool is an on-the-fly CSS Style Editor, which will allow you to change the code in CSS stylesheets directly within the browser.

Other changes in Firefox for PCs include support for Google's SPDY protocol for faster and safer site loading, as well as personal data import from Chrome. This includes bookmarks, cookies, and history. Password, form data, and settings will come at a later date.

You can read full release notes for Firefox 11 here.

Updated Wednesday, March 14, 2012, at 1:45 p.m. PT: Mozilla's senior director of Firefox engineering, Johnathan Nightingale, has updated his Monday blog post that explained why Firefox 11 might have been delayed. The browser was released on time Tuesday, but because of stability concerns caused by this week's large and critical Patch Tuesday security releases from Microsoft, you can only manually upgrade to Firefox 11 at this time. (Download files are available at the top of this story.) We'll update this story again when Mozilla decides to push out automatic upgrades to Firefox 11.

If you are a current Firefox user, you can manually upgrade by going to the Help Menu and clicking About Firefox. The download will automatically start.